Nectophotometer: An Infrared Motility Monitor Used to Rapidly Identify Toxicity in Effluents and Receiving Waters

摘要

A change in the motility pattern of fish and aquatic invertebrates when initially exposed to a toxin has long been used in tests designed to signal the presence of toxins in effluents and receiving waters. We have discovered that the level of motility change occurring within 2.5 hours of exposure to all concentrations of a test toxicant correlates well with mortality observed after three days exposure to the toxin, but that the first 30 minutes of exposure is a poor predictor of mortality. Defining this 'best to use exposure time' can increase the sensitivity of toxicity monitoring systems to a weak toxin, one that causes a motility change so minor that it may otherwise go unnoticed. Motility is monitored and automatically recorded using a Nectophotometer, an automated bio-monitor with computer interface that senses interruptions of infrared beams when organisms separately exposed to multiple concentrations of a toxin move through the beams. In our tests changes in the motility of Artemia salina within the first 2.5 hours of exposure predict 3 day mortality with an average accuracy of 89%. The Nectophotometer has promise for allowing rapid assessment of the toxicity to invertebrates and fish, and may also be used to assess airborne toxicity if motile insects respond in a similar manner.